1. Field of the Invention
The invention relates to a light emitting display technology, and in particular to a self-emitting display device for a system for displaying images capable of suppressing threshold voltage shift while preventing reduction of aperture ratio and a method for fabricating the same.
2. Description of the Related Art
Recently, with the development and wide application of electronic products such as mobile phones, PDAs, and notebook computers, there has been increasing demand for flat panel displays (FPDs) which consume less electric power and occupy less space. Organic electroluminescent/light-emitting devices (OELDs/OLEDs) are self-emitting and highly luminous, with a wider viewing angle, a faster response speed, and a simple fabrication process, making them an industry display of choice.
The current trend in FPD technology is for development of an organic electroluminescent display with higher luminescent efficiency and longer operating lifespan. Accordingly, an active matrix (AM) organic electroluminescent device with thin film transistors has been developed.
An AMOLED typically employs polysilicon (poly-Si) or amorphous silicon (α-Si) as an active layer for a thin film transistor (TFT). However, electrons for such an active layer, may be trapped in the gate dielectric layer during device operation, resulting in threshold voltage (Vth) shift. The luminance of OLEDs depends on injection current (Id). Thus, increased threshold voltage may result in reduced injection current, which negatively impacts the OLED.